Forum for Science, Industry and Business

New tumour markers: “Spot the differences”

21.06.2007

The term “cancer” (from the Greek karkinos, which means sea crab) was used for the first time by Greek doctor Hippocrates five hundred years b.C. to define the tumours that he observed in his patients. Nowadays it is still difficult to diagnose, and prognosis is bad. Cancer is already the main cause of death in many countries, ranking even above cardiovascular diseases.

Pancreatic cancer (PC), the subject of this thesis, has the poorest prognosis of all cancers: the survival rate after five years with the disease is less than 5% and on average, patients who have been diagnosed with it do not live longer than six months.

The modus operandi of cells is well known: the genes (DNA) are the masterminds of the system and their role is to give orders. Those orders are transmitted in the form of messages (RNA), which ultimately become molecules that do the work (proteins). Since all cells have similar genes, they are all able to give the same range of orders. However, depending on their role and the signs and information they receive from their surroundings, each cell type sends only specific messages at any one time. While in normal cells this process is carried out following an organized pattern, this pattern of messages changes completely in cancer cells. When pancreatic cells transform into cancer cells, they abandon their usual functions and start sending abnormal messages, which encourage them to quickly divide and invade nearby tissues.

The aim of this PhD was to intercept messages sent by cancerous pancreatic cells and compare them with those sent by healthy pancreatic cells. This comparison would indicate which orders (messages) are the ones that make the cancer grow and invade and which weapons (proteins) it uses to do so. In order to carry out this work we used microarrays or DNA-chips, a technique used for multiple analyses. It allows the detection and quantification of messages sent by thousands of genes. We analysed biopsies of PC as well as samples of healthy pancreas. The RNA (thousands of messages sent by cells) from each sample was extracted and fluorescently labelled. The RNA has the ability to join complementary DNA. The organized DNA fragments contained on a microarray can detect all possible messages sent by the nearly 30,000 genes that exist in the human genome. When RNA is exposed to the microarray, each message binds to its matching DNA, producing fluorescent signal.

The next step was to compare the images obtained from tumour cells with the ones from normal cells. As we do when we solve “Spot the difference” puzzles, we try to find out what makes drawing A different from drawing B; in this case, which messages are being sent by cancerous cells but not by normal cells. However, here we do not have easy drawings with just a few lines as in a puzzle (Figure A). Instead, we compare complex images with hundreds of thousands of different intensity points. In our study we identified a total of 116 messages that were over-expressed in cancerous cells.

These findings reveal some of the orders that allow pancreatic tumours to grow quickly, feed and invade other tissues. Additionally, these messages and the proteins for which they code are potential diagnostic markers and targets to tackle when developing new anti-cancer treatments.

Finally, we generated antibodies that detect the proteins coded by some of the messages. Using a microscope and colour-labelled antibodies, we managed to dye PC cells and to distinguish them from cells of a healthy pancreas or a pancreas with chronic pancreatitis (Fig. B). These results indicate the usefulness of this marker and establish the basis for the development of a differential diagnostic system for PC.

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...